Horizontal drilling and milling machine with a headstock moving up and down in guides

Abstract

A horizontal drilling and milling machine comprises a vertically movable headstock and a spindle sleeve mounted for horizontal run-out from the headstock. Typically, an outer end of the spindle sleeve undergoes a vertical deflection relative to the headstock during run-out, which deflection is an exponential function of the extent of the run-out. A correcting means is connected to the headstock to move the latter as the run-out proceeds, to effect a vertical correction displacement of the forward end of the spindle sleeve, which displacement is the same exponential function of the extent of the run-out as that of the vertical deflection relative to the headstock. Correction is achieved by comparing a signal indicative of the extent of the run-out, with a predetermined exponential function for the particular spindle sleeve and tool, and generating a suitable correction signal in response thereto. A memory and computer device is employed to make the necessary comparison. The memory and computer device transmit a signal to a motor, which motor is arranged to displace a reversing roll around which a cable is extended. The ends of the cable are connected between the headstock and counterweight. Radial movement of the reversing roll causes the headstock to be inclined in a vertical plane. A motion transmitting mechanism between the motor and the reversing roll enables precise movements to be made even by a motor rotating at high rpm.

What is claimed is: 
     
       1. In a horizontal drilling and milling machine of the type comprising a vertically movable headstock, a spindle sleeve mounted for horizontal run-out from said headstock such that an outer end of said spindle sleeve undergoes a vertical deflection relative to said headstock, which deflection is an exponential function of the extent of said run-out, and correcting means comprising a counterweight at least two reversing rolls, two cables traveling over said reversing rolls to form first and second generally vertical cable sections connected, respectively, to said counterweight and said headstock, and means for displacing said first cable section to move said headstock in a vertical plane in response to said run-out, the improvement comprising: means constraining said counterweight for vertical movement and preventing horizontal displacement thereof,   means mounting the first of said reversing rolls for movement in a radial direction to move said first cable section in a manner displacing said headstock in a vertical plane, and said correcting means including:     sensing means for sensing the extent of horizontal run-out of said spindle sleeve and emitting run-out signals corresponding thereto;   a memory and computer apparatus for storing said exponential function, said memory and computer apparatus arranged to receive said run-out signals from said sensing means and emit deflection compensation signals which are an exponential function of the extent of horizontal run-out, and   displacement means connected to said memory and computer apparatus and responsive to said deflection compensation signals for radially moving said first reversing roll to incline said headstock in a vertical plane about a horizontal axis in a manner effecting a vertical correction displacement of said outer end of said spindle sleeve, which displacement is an exponential function of the extent of said horizontal run-out so as to maintain said outer end of said spindle sleeve on a zero deflection path.   
     
     
       2. Apparatus according to claim 1, wherein said reversing roll is adjustable horizontally and in the same direction as the run-out of said spindle sleeve. 
     
     
       3. Apparatus according to claim 1, wherein said adjustable reversing roll comprises one of two reversing rolls over which said cable passes, and further including a pair of additional reversing rolls and an additional cable passing over said additional reversing rolls to form additional vertical cable sections connected to said counterweight and said headstock. 
     
     
       4. Apparatus according to claim 1, wherein said correcting means comprises a motor, motion transmitting means interconnecting an output shaft of said motor and said reversing roll for radially moving said reversing roll in response to rotation of said output shaft, and a rotation indicator connected to said compensating means and said motor for controlling the rotation of the motor in response to deflection compensation signals from said memory and computer apparatus. 
     
     
       5. Apparatus according to claim 1, wherein said motion transmitting means comprises an internally threaded nut, and a bushing aligned therewith, said nut and bushing arranged to rotate about a common axle, a spindle mounted within said bushing for rotation therewith and for longitudinal movement relative to said nut, said spindle having a threaded end threadedly connected within said nut, and means connecting said output shaft with said nut and bushing to rotate said nut and bushing in the same direction at different rotary speeds.